Since my site was transfered to a new server by my hosting company, my $_SESSION data is not being saved.

I have set the variables via my php.ini file as instructed, although never had to do this before, (eg session.save_path = /home/user/tmp).
The session files are being created in the correct folder, but are always empty.

Only that :
1) The session files are being created in the specified folder on a session initiating - the permissions for each file are 600
2) Perms for the folder itself are 755
3) I can use fwrite to write test data to a selected session file, but calling $_SESSION variables or even using session_register() caused no data to be written to the file.